System for cooling an engine block cylinder bore bridge

ABSTRACT

An engine is provided with an open deck cylinder block having an open water jacket that surrounds a plurality of cylinders that are joined together in a Siamese design by a cylinder bore bridge. The engine also includes a cylinder head gasket, and a cylinder head. For the purpose of removing excess heat from the cylinder bore bridge, cooling channels are provided that allow coolant to flow from the engine block water jacket, across the cylinder bore bridge, and into a cylinder head coolant passageway. In addition, coolant is prevented from flowing from the water jacket on one side of the cylinders, across the bore bridge, and into the water jacket on the other side of the cylinders.

TECHNICAL FIELD

This disclosure relates to cooling an internal combustion engine havinga cylinder block with Siamese cylinders.

BACKGROUND

Internal combustion engines include cooling systems for removing excessheat that is produced from the combustion of fuel and friction of movingcomponents. Removal of the excess heat is necessary to prevent themechanical failure of engine components. The cooling systems typicallyinclude a liquid coolant that is pumped through passageways (sometimesknown as water jackets) in the engine block, cylinder head, and otherengine components. Heat is transferred to the liquid coolant from theengine components when the coolant flows through the various passagewaysin the engine components. Heat is then transferred from the liquidcoolant to the surrounding environment through a heat exchanger, such asradiator. Once the heat is transferred to the surrounding environment,the liquid coolant is redirected through the passageways in the enginecomponents and the process is repeated.

An internal combustion engine having cylinders that share a common wallis known as a “Siamese design” and the common wall is known as the “borebridge.” The bore bridge will experience high temperatures because it isin close proximity to the two combustion chambers of the adjacentcylinders, and to the two sets of piston rings that transfer heat to thecylinder block. Packaging of a cooling system in the area of the borebridge is also difficult adding to the increased temperature of theregion.

Various efforts have been made to cool the bore bridge. It is known todrill cooling channels within the bore bridge that extend between thewater jacket in the engine block and the cylinder head. Thisconfiguration presents limitations in the flow of the liquid coolantthrough channels in the bore bridge because of a limited pressuredifferential and channel cross sectional area.

It would be desirable to provide a cooling channel in the bore bridgethat has an adequate pressure differential and flow area to allow liquidcoolant to sufficiently flow through the channel.

SUMMARY

In at least one embodiment, an engine is provided having an open deckcylinder block that has a deck with an open water jacket that surroundsa number cylinders, and has a Siamese design where the cylinders share acommon wall known as the bore bridge. The bore bridge includes a coolingchannel that is open to the deck and extends across the bore bridge fromthe water jacket on one side of the cylinder to an end point short ofthe water jacket on the other side. A cylinder head gasket has a bottomsurface that is disposed of on the deck of the cylinder block, and acylinder head has a face surface that is disposed of on a top surface ofthe cylinder head gasket. The cooling channel cooperates with waterjacket to enable coolant to flow from the water jacket to an inlet portin the cylinder head, the inlet port being located proximate to the endpoint of cooling channel.

In at least one additional embodiment, an open deck cylinder block isprovided. The open deck cylinder block has an open water jacket thatsurrounds the cylinders and has a Siamese design where the cylindersshare a common wall known as the bore bridge. The bore bridge includes acooling channel that is open to the deck and extends across the borebridge from the water jacket on one side of the cylinder to an end pointshort of the water jacket on the other side.

In at least one additional embodiment, a cylinder head gasket for use inan engine having an engine block with an open deck Siamese cylinderdesign is provided. The generally planar gasket body has an uppersurface that cooperates with cylinder head and a lower surface thatcooperates with a deck surface of an engine block. The cylinder headgasket has an inlet port in the lower surface that is open to the waterjacket in the cylinder block and is adjacent to one side of a cylinderbore bridge that is formed between two Siamesed cylinders. An outletport is formed in the upper surface of the cylinder head gasket and isadjacent to an opposite side of the cylinder bore bridge and open to acylinder head coolant passageway. The outlet port is also sealed fromthe water jacket on the opposite side of the cylinder bore bridge. Afirst elongate cooling channel in the cylinder head gasket extendsbetween the inlet and outlet ports for overlying and open to a secondelongate cooling channel in the cylinder bore bridge, which enablescoolant to flow from the water jacket on one side of the cylinder borebridge, across the cylinder bore bridge, to the cylinder head coolantpassageway on the opposite side of a cylinder bridge. The first elongatechannel flares out at the outlet port to maintain a minimum summed crosssectional flow area of the first and second channels as a crosssectional flow area of the second elongate channel decreases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is an exploded isometric view of the engine;

FIG. 1 b is an alternative embodiment of the cylinder head gasket;

FIG. 2 is a transverse cross-sectional view taken along the line 2-2 ofFIG. 1 a;

FIG. 3 is a similar to FIG. 2, but shows alternative embodiments of thecylinder head and cylinder head gasket, the cylinder head gasket is notto scale and is shown with an increased thickness for ease ofillustration;

FIG. 4 is a plan view of the head gasket in FIG. 3;

FIG. 5 illustrates a graph having a plot of the summed cross sectionalflow areas of cooling channels in the cylinder block and head gasketversus a distance X; and

FIG. 6 is partial longitudinal cross-sectional view taken along ling 5-5of FIG. 1.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

An exploded view of an internal combustion engine 10 according thepresent disclosure is illustrated in FIG. 1 a. The engine 10 includes anopen deck cylinder block 12, a cylinder head gasket 14, and a cylinderhead 16. The cylinder head gasket 14 has a lower surface 18 that isdisposed of on the deck surface 20 of the cylinder block 12, and thecylinder head 16 has a face surface 22 that is disposed of on the uppersurface 24 of the cylinder head gasket 14.

FIGS. 1 a and 2 show the cylinder block 12 having four cylinders 26 witha Siamese design, where the adjacent cylinders 26 share a common wallknown as the bore bridge 28. The deck surface 20 of the cylinder block12 is open to a water jacket 30 that surrounds the cylinders 26. Coolingchannels 32 located on the cylinder bore bridges 28 extend a length Lfrom the water jacket 30 on one side of the bore bridge 28 to end points34 short of the water jacket 30 on the other side of the bore bridge 28.

Still referring to FIGS. 1 a and 2, the cylinder head gasket 14 hasopenings 36 that allow coolant to flow from the water jacket 30 in thecylinder block 12 into a cooling passageway 38 located in the cylinderhead 16. Additional openings 40 in the cylinder head gasket 14 allowcoolant to flow from the water jacket 30 in the cylinder block 12 intothe cooling channels 32 located on the cylinder bore bridges 28, fromthe cooling channels 32 into inlet ports 42 in the cylinder head 16,which are located proximate to the to end points 34 short of the waterjacket 30 on the other side of the bore bridge 28, and from the inletports 42 into the cooling passageway 38 in the cylinder head 16. Thecylinder head gasket 14 also creates a seal preventing coolant fromflowing from the water jacket 30 on one side the cylinder bore bridge28, across the cooling channels 32, and into the water jacket 30 on theother side of the cylinder bore bridge 28.

Referring to FIG. 1 b, an alternative embodiment to the cylinder headgasket 44 is illustrated. The cylinder head gasket 44 includes openings46 that connect the water jacket 30 in the cylinder block 12 on one sideof the bore bridge 28 to the cooling passageway 38 in cylinder head 16on the same side of the bore bridge. The openings 46 also connect thewater jacket 30 in the cylinder block 12 on one side of the bore bridge28 to the inlet ports 42 in the cylinder head 16 proximate the endpoints 34 short of the water jacket 30 on the other side of the borebridge 28. This embodiment of the cylinder head gasket 44 also creates aseal preventing coolant from flowing from the water jacket 30 in thecylinder block 12 on one side the cylinder bore bridge 28, across thecooling channel 32, and into the water jacket 30 in the cylinder block12 on the other side of the cylinder bore bridge 28. Additional openings48 allow coolant to flow directly from the water jacket 30 in cylinderblock 12 into the cooling passageway 38 in the cylinder head 16 on theside of the cylinder bore bridge 28 opposite of the cooling channel 32.

Referring to FIGS. 3 and 4, an additional alternative embodiment of thecylinder head gasket 114 and an alternative embodiment of the cylinderhead 116 are provided. The cylinder head gasket 114 has a lower surface118 that is disposed of on the deck surface 20 of the cylinder block 12,and the cylinder head 116 has a face surface 122 that is disposed of onan upper surface 124 of the cylinder head gasket 114.

The cylinder head gasket 114 includes cooling channels 126. The coolingchannels include inlet ports 128 that cooperate with the water jacket 30of the cylinder block 12 allowing coolant to flow from the water jacket30 into the cooling channels, and outlet ports 130 that cooperate withthe cooling passageway 138 in the cylinder head 116, allowing coolant toflow from the cooling channels 126 into the cooling passageway 138.Between the water jacket 30 of the cylinder block 12 and the coolingpassageway 138 in the cylinder head 116, the cooling channels 126 areopen to and adjacent to the cooling channels 32 located on the cylinderbore bridge 28. At the outlet port 130, the cooling channel 126 includesa step 132 that creates a seal between the cooling channel 126 and thewater jacket 30 on the other side of the bore bridge 28.

Referring to FIGS. 3, 4, and 5, the cooling channels 126 in the cylinderhead gasket 114 and the adjacent cooling channel 32 located on thecylinder bore bridge 28, have a summed cross sectional flow area. Thissummed cross sectional flow area is demonstrated by the graph in FIG. 5.The summed cross sectional flow area is maintained nearly constant inthe proximity of a center point C of the cooling channel 126. Also, thesummed cross sectional flow area will have a value equal to at least thevalue of the summed cross sectional area at the center point C, as youmove in the direction X from the inlet port 128 of the cooling channel126 to the outlet port 130. Setting the minimum value of the summedcross sectional flow area at the center point C will ensure that theflow of coolant is not restricted.

Referring to FIGS. 4 and 5, the portion of the cooling channel 126 ofthe cylinder head gasket 114 near the inlet port 128 has a large crosssectional flow area because the cooling channel 126 near the inlet port128 is not running adjacent to the cooling channel 32 located on thecylinder bore bridge 28. As you move in the direction X, away from theinlet port 128 and toward the center point C, the portion of the summedcross sectional flow area represent by the cooling channel 126 (markedA) decreases as the portion summed cross sectional flow area representedby the cooling channel 32 (marked B) increases. As you move in thedirection X, away from the center point C toward the outlet port 130,the cross sectional flow area B of the cooling channel 32 will begin todecrease at a point D beyond the center point C. When the crosssectional flow area B of the cooling channel 32 begins to decrease atpoint D, the cooling channel 126 begins to open up at the outlet port130 and the cross sectional flow area A of the cooling channel 126 willbegin to increase to ensure the summed cross sectional flow area remainsat or above the value of the summed cross sectional flow area at thecenter point C.

Referring to FIG. 6, a partial cross section of the cylinder block 12shows a set of adjacent Siamesed cylinders 26 with pistons 134. Thecooling channels 32 of the bore bridge 28 are shown having a depth Y anda width Z.

Although the preferred embodiments described above were directed to opendeck cylinder blocks, the invention should not be construed as limitedto open deck cylinder blocks and should include both open and closeddeck cylinder blocks.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

What is claimed is:
 1. An engine comprising: a cylinder block having adeck and a water jacket surrounding a plurality of cylinders joinedtogether in a Siamese design by a cylinder bore bridge, the cylinderbore bridge having a cooling channel formed therein open to the deckextending substantially across the cylinder bore bridge from the waterjacket on one side to an end point short of the water jacket on theother side; a cylinder head gasket having a top and bottom surface, thebottom surface disposed of on the deck; and a cylinder head having aface surface, the face surface disposed of on the top surface of thecylinder head gasket, wherein the cooling channel cooperates with thewater jacket to enable coolant to flow from the water jacket through thecooling channel to an inlet port in the cylinder head face surfaceproximate the cooling channel end point.
 2. The engine of claim 1,wherein the cooling channel of the cylinder bore bridge has a depth Yfrom the deck of the cylinder block being at least 3.0 mm.
 3. The engineof claim 2, wherein the depth Y ranges between 3.0 mm and 8.0 mm.
 4. Theengine of claim 1, wherein a length L of the cooling channel extendsover at least 70% of the length of the cylinder bore bridge.
 5. Theengine of claim 4, wherein the length L of the cooling channel extendsfrom 80% to 95% across the length of the cylinder bore bridge.
 6. Theengine of claim 1, wherein the cooling channel of the cylinder borebridge has a width Z being at least 0.75 mm.
 7. The engine of claim 6,wherein the width Z ranges between 1.0 mm and 2.0 mm.
 8. The engine ofclaim 1, wherein the cylinder head gasket cooperates with the coolingchannel in the cylinder bore bridge allowing coolant to flow from thewater jacket, through the cooling channel, and into the inlet port inthe cylinder head face surface proximate the cooling channel end point.9. The engine of claim 8, wherein the cylinder head gasket prevents thecoolant from flowing through the cooling channel from the water jacketon one side of the cylinder bore bridge to the water jacket on the otherside.
 10. The engine of claim 9, wherein the cylinder head gasket has asecond cooling channel that is adjacent and open to the cooling channelon the cylinder bore bridge.
 11. The engine of claim 1, wherein thecylinder block has an open deck.
 12. An open deck engine cylinder blockhaving an open water jacket surrounding a plurality of cylinders joinedtogether in a Siamese design by a cylinder bore bridge, the cylinderbore bridge having a cooling channel formed therein open to the deckextending substantially across the cylinder bore bridge from the waterjacket on one side to an end point short of the water jacket on theother side.
 13. The cylinder block of claim 12, wherein the coolingchannel of the cylinder bore bridge has a depth Y from the deck of thecylinder block being at least 3.0 mm.
 14. The cylinder block of claim13, wherein the depth Y ranges between 3.0 mm and 8.0 mm.
 15. Thecylinder block of claim 12, wherein a length L of the cooling channelextends over at least 70% of the length of the cylinder bore bridge. 16.The cylinder block of claim 15, wherein the length L of the coolingchannel extends from 80% to 95% across the length of the cylinder borebridge.
 17. The cylinder block of claim 12, wherein the cooling channelof the cylinder bore bridge has a width Z being at least 0.75 mm. 18.The cylinder block of claim 17, wherein the width Z ranges between 1.0mm and 2.0 mm.
 19. The engine of claim 12, wherein the cylinder blockhas an open deck.
 20. A cylinder head gasket for use in an engine havinga cylinder block with a Siamese cylinder design, the gasket comprising:a generally planar gasket body having an upper surface for cooperationwith a cylinder head and a lower surface for cooperating with a decksurface of a cylinder block, the gasket having formed therein: an inletport in the lower surface open to a water jacket in the cylinder blockadjacent to one side of a cylinder bore bridge formed between twoSiamesed cylinders; an outlet port formed in the upper surface adjacentto an opposite side of the cylinder bore bridge, open to a cylinder headcoolant passageway and sealed from the water jacket in the cylinderblock; and a first elongate cooling channel extending between the inletand outlet ports for overlying and open to a second elongate coolingchannel in the deck surface of a cylinder block extending partiallyacross the cylinder bore bridge from the water jacket adjacent the inletport and terminating at an end point short of the water jacket on theother side, enabling coolant to flow from the water jacket on one sideof the cylinder bore bridge, across the cylinder bore bridge, to thecylinder head coolant passageway on the opposite side of the cylinderbore bridge, wherein, the first elongate cooling channel flares outprior the second elongate cooling channel end point to maintain aminimum summed cross sectional flow area of the first and secondchannels as a cross sectional flow area of the second elongate channeldecreases.